Dune Double Feature

Dune: Part One

In the distant future, Duke Leto Atreides is assigned by the Padishah Emperor Shaddam IV to replace Baron Vladimir Harkonnen as the fiefholder of Arrakis, a harsh desert planet and the sole source of "spice", a valuable psychotropic substance that imparts heightened vitality and awareness. Spice is also key to interstellar travel. Emperor Shaddam, fearful of Leto's rising power, plots for House Harkonnen, aided by his Sardaukar troops, to retake Arrakis and destroy House Atreides. Leto is suspicious of the Emperor but weighs the risks against the power of controlling Arrakis and making an alliance with its mysterious natives, the Fremen.
Leto's concubine, Lady Jessica, is an acolyte of the Bene Gesserit—a sisterhood whose members possess advanced physical and mental abilities. As part of a centuries-long breeding program, they instructed her to bear a daughter whose son would become the Kwisatz Haderach—a messianic superbeing with the prescience necessary to guide humanity to a better future. Jessica disobeyed and bore a son, Paul, whom she trains in Bene Gesserit practices. Paul also receives mentorship from Leto's aides Duncan Idaho, Gurney Halleck, Wellington Yueh, and Thufir Hawat. The Reverend Mother and Imperial Truthsayer Gaius Helen Mohiam subjects Paul to a highly dangerous gom jabbar test to assess his humanity and impulse control, which he passes. Paul begins having troubling visions of the future.
House Atreides arrives on Arrakis. The Fremen revere Paul and Jessica, which she explains is due to the Bene Gesserit sowing beliefs on Arrakis centuries earlier. An attempt to assassinate Paul fails. At a secret meeting on the Harkonnen planet Giedi Prime, Mohiam insists that Baron Harkonnen spare Paul and Jessica in his coup, to which he duplicitously agrees. Leto meets and negotiates with Fremen chieftain Stilgar and meets the Imperial Judge of the Change, Dr. Liet Kynes, a planetologist who lives among the Fremen. During a flight over the desert, they rescue a stranded spice-harvesting crew from a giant sandworm, and Paul's exposure to the spice triggers intense premonitions.
Yueh betrays the Atreides and disables Arrakeen's shields, allowing the Harkonnens and Sardaukar to invade. Yueh incapacitates Leto, planning to exchange him for his wife, the Baron's prisoner. Yueh replaces one of Leto's teeth with a poison gas capsule with which Leto can assassinate the Baron. After the Baron kills Yueh, Leto releases the gas, killing himself and the Baron's Mentat, Piter De Vries, but the Baron survives. Though the Baron arranged to have Paul and Jessica dropped deep in the desert to die, Yueh had left them with a fremkit with survival supplies. Jessica uses the Voice technique to overpower and kill their captors. Overnighting in the desert, Paul—surrounded by spice—has visions of a bloody holy war fought across the universe in his name.
After conquering Arrakis, Baron Harkonnen appoints his nephew Rabban to oversee the planet, and orders him to restart spice production to recoup the invasion's cost. Meanwhile, Duncan and Kynes find Jessica and Paul, who discloses his plan to marry one of Emperor Shaddam's daughters to avert a potential civil war arising from the Emperor's betrayal. When they are discovered by Sardaukar soldiers, Duncan sacrifices himself to enable Paul and Jessica to escape. Kynes also tries to escape but is caught and mortally wounded. Deep in the desert, Paul and Jessica encounter Stilgar's tribe, including Chani, the young woman from Paul's visions. When Stilgar commands lenience towards Paul and Jessica, the Fremen warrior Jamis challenges them to a ritual duel to the death; Paul accepts and wins. Contrary to Jessica's wishes, Paul joins the Fremen, determined to fulfill his father's goal of bringing peace to Arrakis.

Dune: Part Two

Following the defeat of House Atreides by House Harkonnen, Princess Irulan—daughter of the Padishah Emperor, Shaddam Corrino IV—records in her journal her father's betrayal of the Atreides. On the planet Arrakis, a Fremen tribe led by Stilgar accompanies Paul Atreides and his pregnant Bene Gesserit mother Lady Jessica to Sietch Tabr. Some Fremen suspect they are spies, while Stilgar and others see signs of the prophecy that a mother and son from the "Outer World" will bring prosperity to Arrakis.
After Paul defeats Jamis in a duel, the Fremen accept Paul. Stilgar commands Jessica to succeed Sietch Tabr's dying Reverend Mother by ritually drinking the normally fatal Water of Life. Jessica uses her Bene Gesserit training to transmute the poisonous liquid and survive, inheriting the memories of past Reverend Mothers. The liquid prematurely awakens the mind of her unborn daughter, Alia, allowing Jessica to communicate with her. Chani and her friend Shishakli correctly deduce that the prophecy is a Bene Gesserit myth fabricated to manipulate the Fremen. Nonetheless, Chani begins to respect Paul after he declares that he only seeks to fight alongside the Fremen, not rule them.
Paul and Chani fall in love as he immerses himself in Fremen culture—learning their language, becoming a Fedaykin fighter, riding a sandworm, and raiding Harkonnen spice-harvesting operations. Paul adopts the Fremen names Usul and Muad'Dib. Due to the spice raids, Baron Vladimir Harkonnen replaces his older nephew Rabban as the ruler of Arrakis with his favored nephew, Feyd-Rautha. Lady Margot Fenring is sent by the Bene Gesserit to evaluate Feyd-Rautha as a prospective Kwisatz Haderach.
Jessica travels south to unite with Fremen fundamentalists who strongly believe in the prophecy. Paul remains in the north, fearful that his visions of an apocalyptic holy war will come to pass if he goes south as a messiah. During a raid on a smuggler spice harvester, Paul reunites with his mentor Gurney Halleck, who leads Paul to House Atreides' hidden atomic warheads. Paul is forced to journey south after Feyd-Rautha unleashes a devastating attack on Sietch Tabr and kills Shishakli. Upon arrival in the south, Paul drinks the Water of Life and falls into a coma. Jessica uses The Voice to compel Chani to save Paul; she gives Paul a mixture of her tears with the Water of Life, which awakens him. With his emerging prescience, Paul perceives countless possible futures and identifies a narrow path to victory, along with a vision of an adult Alia on a water-covered Arrakis. He also discovers that his mother is the Baron's daughter and that the Bene Gesserit orchestrated her union with Duke Leto Atreides to merge Harkonnen and Atreides bloodlines in their plan to create the Kwisatz Haderach.
Paul declares himself the messianic figure Lisan al Gaib after gaining the southern Fremen's support by demonstrating his ability to know their deepest thoughts. He threatens to destroy the spice fields, forcing Emperor Shaddam to come to Arrakis with Irulan and his elite Sardaukar soldiers. The Fremen launch an offensive using atomic weapons and sandworms, overpowering the Sardaukar. Gurney leads a Fremen assault on Arrakeen, killing Rabban.
After capturing the Imperial court and executing Vladimir Harkonnen, Paul challenges Shaddam for the throne and, to Chani's dismay, demands to marry Irulan. More Great Houses (which were secretly summoned by the Baron) arrive in orbit but Paul threatens to destroy the spice fields if they intervene. Feyd-Rautha, who volunteers to be Shaddam's champion, is killed by Paul in a duel. Irulan agrees to marry Paul on the condition that he spare her father. Shaddam surrenders but the Houses reject Paul's ascendancy, so he orders the Fremen to attack the orbiting fleet. As Stilgar leads the Fremen onto the captured Sardaukar ships, Jessica and Alia reflect on the beginning of Paul's holy war. A devastated Chani refuses to bow to Paul and departs alone on a sandworm.